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I ' 14 May 2001 AGE-NC Project No 95-0130 ' Page 4 of 5 area bound by wells MW-1, MW-3 and MW-5, ground water flow was inferred towards the ' east-northeast at a gradient of 0 005 fl/ft In the area bound by wells MW-1, MW-2, MW-3 and MW-4 ' - Due to the low hydraulic gradient at the site, slight variations In ground water measurements or changes of recharge/discharge of the local ground water could greatly modify the inferred ground water flow direction ' - Ground water at the site Is approximately seventeen to twenty-two feet above (drowned)the screen Intervals at wells MW-1,MW-2,MW-3 and MW-4(I a screened below ground water elevation), and may not yield samples fully representative of shallowest ground water conditions, wells VW-1C, VW-2A and VW-3A are approximately five to ten feet "drowned" The ground water elevation appeared to be wlthing the screen Intervals of wells ' VW-1B, VW-2B and VW-3B and should be representative of shallowest ground water conditions (Figures 6 and 7) - The increase of ground water elevation of approximately 121 feet between the October 2000 and the February 2001 monitoring events Is probably part of the seasonal fluctuation - The estimated extent of dissolved hydrocarbon-Impact Is depicted In cross sectional views GC'and D D'(Figures 6 and 7) TBA was detected In samples from wells MW-3, MW-5 and VW-2B The only detection of off-site dissolved TBA was In the sample collected from crossgradlent well MW-5 at a concentration of 110 µg/1 Based on data collected from the Intervening well VW-1, the TBA-Impact detected in well MW-5 may not be related to the Top Filling Station - Based on previous MTBE concentrations reported at MW-1, a substantial increase of MTBE was reported at MW-1 during the February 2001 monitoring event, the Increase may be I related to westward (lateral) movement of the dissolved MTBE plume The elevated concentrations of petroleum hydrocarbons detected In samples collected from wells VW-1, VW-2 and VW-3 indicate that these wells are within or near the dissolved ' petroleum hydrocarbon"core area" of the plume (Figures 4, 5, 6 and 7) The lateral extent of the dissolved petroleum hydrocarbon plume Is not known toward the west, northwest, north, northeast and east of the area bound by wells MW-1 through VW-3, the vertical extent Is not known In any area(Figures 4, 5, 6 and 7) - The greatest concentrations of dissolved TPH-g and BTEX were detected In samples collected from wells VW-1 and VW-2 located near the northern-most former UST pit(Figure 4), the greatest concentration of dissolved MTBE were detected In samples collected from ' well VW-3 located near the southern-most former UST pit (Figure 5) and MW-1 located • west of the former UST pit which suggests at least two separate releases Advanced GeoEnvironniental,Inc I